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In my opinoin, yes it is.
I also use a warthog, but I have mine on a mount that places it between my knees (lesss arm/neck/back pain).
It's easiest at cruise settings and at a bit of altitude, i.e. above 10,000ft.
The controls are super sensitive in the spitfire, so at low altitudes with thick (responsive) air it's harder.
Also, at high boost and RPM the engine is pulling the thing through the air so hard that trimming out is a lot more difficult. Relax the engine, then relax the air-frame.

Glad to hear it is not just my old body that aches after a long session in the Spit. Man it is the only plane that actually hurts to fly.

I spent a few days ago building a bracket for my Stick to place it center, but the desk layout is jut not right and was very uncomfortable so went back to stick on right hand side of keyboard method. Currently investigating other options.

I find the trim very strange in the Spit, if you slow down you pitch up which seems a bit out of whack to me, but somebody posted in one of my other threads that as she slows, her tail gets heavy. I think it is just going to be a lot more practice.

Learn to actually do less. When I started learning the ropes with the Spit in DCS, I constantly overdid turns by pulling too hard and too quickly, engine settings too high, etc. The result was I wasted energy and degraded the structural integrity of my plane very quickly ending in ripped off wings or broken engines. So forcing yourself to do things slower is a big part of flying energy efficient and "clean". I still do it today when I switch over from another sim and I require time to acclimate to DCS. So try not to mix sims, it messes with your head.

To the high G turns and whatnot:
It's related to how stick forces are modelled in the game. DCS in general limits you much less than other sims. This results in your pilot being able to pull enormous Gs at times because the game does not limit the deflection speed (exception being the 109 which was a hot discussed topic at the time). Other sims start to reduce the input once your airspeed increases. Technically, the DCS approach is more correct but it leads to weirdness due to the virtual pilot being a big green mountain of muscles going "HULK PULL!" on the stick.

Learn to actually do less. When I started learning the ropes with the Spit in DCS, I constantly overdid turns by pulling too hard and too quickly, engine settings too high, etc. The result was I wasted energy and degraded the structural integrity of my plane very quickly ending in ripped off wings or broken engines. So forcing yourself to do things slower is a big part of flying energy efficient and "clean". I still do it today when I switch over from another sim and I require time to acclimate to DCS. So try not to mix sims, it messes with your head.

To the high G turns and whatnot:
It's related to how stick forces are modelled in the game. DCS in general limits you much less than other sims. This results in your pilot being able to pull enormous Gs at times because the game does not limit the deflection speed (exception being the 109 which was a hot discussed topic at the time). Other sims start to reduce the input once your airspeed increases. Technically, the DCS approach is more correct but it leads to weirdness due to the virtual pilot being a big green mountain of muscles going "HULK PULL!" on the stick.

Pretty much this. Also, very few people fail to take into account the short "throw" or travel of our desktop joysticks compared to the long control columns found in the real warbirds. This is where most of the weirdness comes from, and why people do joystick extensions in DCS.

More travel = more sensitive or finer control inputs.

Another solution is FFB. Once you try it it's very hard to go back to a regular spring stick.

What MOST people use though is curves. I personally dislike them and didn't use them even before moving to FFB, but they do make people's lives easier.